Bags stamped with "Theraflu" in red letters have been found on several of the victims. Post-mortem exams have confirmed traces of fentanyl, a drug that can be up to 100 times more powerful than morphine, the base drug in traditional heroin.
The result has been a rash of overdose deaths in Allegheny and surrounding counties, the Pittsburgh Post-Gazette reported Monday.
Allegheny County Medical Examiner Karl Williams said the death rate associated with the "Theraflu" heroin is disturbing.
"We usually deal with 250 drug overdoses a year, so what's going on is really significant," Williams said. "We believe we have identified fentanyl in at least some of the materials we've found at the scenes," he said, adding that the investigation is complicated because the overdose scenes often have multiple materials related to drug use.
"You don't just find [stamp] bags labeled 'Theraflu.' You find five or 20 stamp bags labeled different things."
Notable deaths of 2014 [PHOTOS]